Non-resonant microwave frequency halver

Abstract

A broadband non-resonant microwave frequency halver which simultaneously decouples the input frequency from the output port through phase cancellation and couples the subharmonic frequency to the output port through phase addition providing good isolation between input and output over a very broad frequency range. The implementation of this circuit specifically excludes resonant, or frequency dependent elements and therefore has a much broader band of operation than previous circuits which relied on resonant phenomena.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
       1. A microwave frequency divider comprising: a dielectric substrate with two parallel planar surfaces;   a microstrip line component of conductive material on one of the planar surfaces, the microstrip line component having an input port and two other ports;   a conductive ground plane on the other planar surface;   two varactor diodes with respective first and second terminals, the first terminals being grounded and the second terminals being connected to respective ones of the two other ports of the microstrip line component; and   means for extracting a signal at a frequency f/2 from the microstrip component when a signal at a frequency f is applied to the microstrip component input port, the signal extracting means comprising a slotline in the ground plane havig an output port adjacent the varactor diodes.   
     
     
       2. A broadband microwave frequency divider as defined in claim 1 wherein said first terminals of the varactor diodes are connected to said ground plane. 
     
     
       3. A microwave frequency divider as defined in claim 1, wherein the first terminals are connected to respective broadband microwave short circuits, each short circuit being connected to ground by a high impedance line. 
     
     
       4. A microwave frequency divider as claimed in claim 1 wherein the output port of said slotline is disposed intermediate said varactor diodes and a portion of said output port of said slotline is located in a position adjacent to a junction between the input port of said microstrip line component and the two other ports thereof. 
     
     
       5. A microwave frequency divider according to claim 1, wherein the slotline further comprises a pair of slotline ports symmetrically arranged with respect to and connected to the output port. 
     
     
       6. A broadband microwave frequency divider according to claim 5 in which an electrical connection is made across the output port. 
     
     
       7. A broadband microwave frequency divider according to claim 5 wherein the electrical connection made across the output port is at a junction of said pair of slotline ports.